假设我有一个垂直线性布局:
[v1]
[v2]
默认情况下，v1已经可见= GONE。我想用一个展开动画显示v1，同时下推v2。
我是这样做的:
Animation a = new Animation()
{
int initialHeight;
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
final int newHeight = (int)(initialHeight * interpolatedTime);
v.getLayoutParams().height = newHeight;
v.requestLayout();
}
@Override
public void initialize(int width, int height, int parentWidth, int parentHeight) {
super.initialize(width, height, parentWidth, parentHeight);
initialHeight = height;
}
@Override
public boolean willChangeBounds() {
return true;
}
};
但是用这个解决方案，当动画开始时我有一个眨眼。我认为这是由于v1在应用动画之前显示全尺寸。
用javascript，这是一行jQuery!android有什么简单的方法吗?
public static void expand(final View v, int duration, int targetHeight) {
v.measure(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
v.getLayoutParams().height = 0;
v.setVisibility(View.VISIBLE);
ValueAnimator valueAnimator = ValueAnimator.ofInt(0, targetHeight);
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
v.getLayoutParams().height = (int) animation.getAnimatedValue();
v.requestLayout();
}
});
valueAnimator.setInterpolator(new DecelerateInterpolator());
valueAnimator.setDuration(duration);
valueAnimator.start();
}
public static void collapse(final View v, int duration, int targetHeight) {
ValueAnimator valueAnimator = ValueAnimator.ofInt(0, targetHeight);
valueAnimator.setInterpolator(new DecelerateInterpolator());
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
v.getLayoutParams().height = (int) animation.getAnimatedValue();
v.requestLayout();
}
});
valueAnimator.setInterpolator(new DecelerateInterpolator());
valueAnimator.setDuration(duration);
valueAnimator.start();
}
展开/折叠视图的最佳解决方案:
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
View view = buttonView.getId() == R.id.tb_search ? fSearch : layoutSettings;
transform(view, 200, isChecked
? ViewGroup.LayoutParams.WRAP_CONTENT
: 0);
}
public static void transform(final View v, int duration, int targetHeight) {
int prevHeight = v.getHeight();
v.setVisibility(View.VISIBLE);
ValueAnimator animator;
if (targetHeight == ViewGroup.LayoutParams.WRAP_CONTENT) {
v.measure(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
animator = ValueAnimator.ofInt(prevHeight, v.getMeasuredHeight());
} else {
animator = ValueAnimator.ofInt(prevHeight, targetHeight);
}
animator.addUpdateListener(animation -> {
v.getLayoutParams().height = (animation.getAnimatedFraction() == 1.0f)
? targetHeight
: (int) animation.getAnimatedValue();
v.requestLayout();
});
animator.setInterpolator(new LinearInterpolator());
animator.setDuration(duration);
animator.start();
}
如果你不想扩展或折叠所有的方式-这里是一个简单的HeightAnimation -
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.Transformation;
public class HeightAnimation extends Animation {
protected final int originalHeight;
protected final View view;
protected float perValue;
public HeightAnimation(View view, int fromHeight, int toHeight) {
this.view = view;
this.originalHeight = fromHeight;
this.perValue = (toHeight - fromHeight);
}
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
view.getLayoutParams().height = (int) (originalHeight + perValue * interpolatedTime);
view.requestLayout();
}
@Override
public boolean willChangeBounds() {
return true;
}
}
用法:
HeightAnimation heightAnim = new HeightAnimation(view, view.getHeight(), viewPager.getHeight() - otherView.getHeight());
heightAnim.setDuration(1000);
view.startAnimation(heightAnim);
@Tom Esterez的回答，但更新为正确使用view.measure()每个Android getMeasuredHeight返回错误的值!
// http://easings.net/
Interpolator easeInOutQuart = PathInterpolatorCompat.create(0.77f, 0f, 0.175f, 1f);
public static Animation expand(final View view) {
int matchParentMeasureSpec = View.MeasureSpec.makeMeasureSpec(((View) view.getParent()).getWidth(), View.MeasureSpec.EXACTLY);
int wrapContentMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
view.measure(matchParentMeasureSpec, wrapContentMeasureSpec);
final int targetHeight = view.getMeasuredHeight();
// Older versions of android (pre API 21) cancel animations for views with a height of 0 so use 1 instead.
view.getLayoutParams().height = 1;
view.setVisibility(View.VISIBLE);
Animation animation = new Animation() {
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
view.getLayoutParams().height = interpolatedTime == 1
? ViewGroup.LayoutParams.WRAP_CONTENT
: (int) (targetHeight * interpolatedTime);
view.requestLayout();
}
@Override
public boolean willChangeBounds() {
return true;
}
};
animation.setInterpolator(easeInOutQuart);
animation.setDuration(computeDurationFromHeight(view));
view.startAnimation(animation);
return animation;
}
public static Animation collapse(final View view) {
final int initialHeight = view.getMeasuredHeight();
Animation a = new Animation() {
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
if (interpolatedTime == 1) {
view.setVisibility(View.GONE);
} else {
view.getLayoutParams().height = initialHeight - (int) (initialHeight * interpolatedTime);
view.requestLayout();
}
}
@Override
public boolean willChangeBounds() {
return true;
}
};
a.setInterpolator(easeInOutQuart);
int durationMillis = computeDurationFromHeight(view);
a.setDuration(durationMillis);
view.startAnimation(a);
return a;
}
private static int computeDurationFromHeight(View view) {
// 1dp/ms * multiplier
return (int) (view.getMeasuredHeight() / view.getContext().getResources().getDisplayMetrics().density);
}
